Camera Tracking - How to Reconstruct LocRotScale Marker To Empty?
Select your empty. Press F3 or spacebar for "SEARCH", type: "bake animation". Select Rotation, Scaling, etc.. Leave everything at default. Press OK.
In a new workspace window, switch to GRAPH EDITOR (shift F6). Select in your outliner the recently baked empty (if it's not already selected), you should open the eye icion in the graph editor, and find the channels you're interested in (rotationXYZ, and ScaleXYZ) now they should contain baked data.

From your question is not cleared if you did the tracking using blender tools of if you're importing it from another software. But at leas if you're inside blender, the previous described procedure should get data into your empty to track or follow.